Our objectives are to exploit our discovery, isolation and partial characterization of two opposing antigen-specific immunoregulatory activities found in T-lymphocyte dialyates: an Inducer Factor (TiF) which augments cell-mediated immunity (CMI) and a Suppressor Factor (TsF) which suppresses CMI in immune cell populations and neutralizes the activity of Inducer Factor on nonimmune cell populations. Specific aims are centered around the logical progress toward production of recombinant Inducer Factor in E. coli, once the amino acid sequences of purified Bovine Inducer Factor and Human Inducer Factor are determined. Studies include: a) continuation of amino acid analyses and beginning amino acid sequencing of nanomole quantities of Diphtheria toxoid specific and Tetanus toxoid specific Bovine Inducer Factors purified by binding to specific antigen and hydrolyzed following recovery from the respective solid-phase immunoadsorbant; b) we plan to continue studies on the production and assay of TiF by hybridoma clones of Leukemia TH cells fused to normal antigen-stimulated TH cells of various antigenic specificities. Knowledge of the amino acid composition and sequence of Bovine Inducer Factor will allow the choice of an appropriate radiolabel to internally radiolabel the hybridoma clones now producing TiF and permit isolation of labelled TiF by specific solid-phase antigen immunoadsorbants and recovery following treatment with 8M urea for amino acid analyses and sequencing; c) similar studies will be done on TiF generated from antigen-stimulated normal TH cells propagated by IL-2 in continuous culture. Additionally, antiidiotypic (antiparatopic) T-cells will be generated in such cultures and their dialysates studied for TiF and TsF activity in the LMI assay in vitro and BALB/c mice footpad reaction in vivo. It is also planned to extend studies to clarify the relationship of TiF to the T-cell receptor for antigen by absorption of dialysates with antibodies directed at putative T-cell receptor molecules. Similar studies are planned to clarify the relationship of TiF to V-region structures using a variety of monoclonal anti-VH antibodies. The Leukocyte Migration Inhibition (LMI) assay will be used as a screening test in the above studies preparatory to and guiding the design of in vivo studies of effects of TiF and TsF and the DTH footpad reaction in BALB/c mice.